South Korea 's Yonhap News Agency said North Korea might be using a vertical cold-launch system to fire the missiles. The system, which is commonly associated with submarine- and ship-based weapons, ejects a missile from its container before the missile ignites midair.

U.S. President Donald Trump said in an interview broadcast on Thursday that he plans to seek to engage North Korean leader Kim Jong Un anew after the two men developed a working relationship in Trump's first term.

Kim Jong Un, who Trump lauded as a "smart guy," has become Russian President Vladimir Putin’s key ally in a war against Ukraine, providing ballistic missiles, artillery, and 12,000 troops.

North Korean leader Kim Jong Un called for bolstering nuclear forces this year during a visit to the country's nuclear material production base and nuclear weapons institute, state media KCNA said on Wednesday.

North Korean leader Kim Jong-un has inspected a nuclear-material production base and a nuclear weapons institute, calling for overfulfilling the plan for producing weapons-grade nuclear materials and strengthening the country's nuclear shield,

Kim Jong Un Vs Trump | Kim Jong Un Nuclear | US News | North Korea News As Donald Trump eyes a potential return to the White House, North Korea's Kim Jong Un is ramping up tensions by showcasing his nuclear arsenal through recent missile tests.